This relates generally to integrated circuit interconnection technologies.
Integrated circuit interconnection technologies connect two electronic components, both mechanically and electrically. For example, solder balls may be used to connect an integrated circuit to a printed circuit board, such as a motherboard. The integrated circuit is placed over the motherboard with intervening solder balls. Upon the application of heat, in a process called reflow, the solder is softened and a solder joint is formed between the devices.
While this type of surface mount or C4 connection has been highly successful, there is a continuing desire to increase the density of interconnections that can be formed. The more interconnections per unit of area that can be formed, the smaller the resulting devices can be. Generally, the smaller the devices, the lower their cost and the higher their performance.
Moreover, existing devices may be prone to a number of failures, including stress or fatigue related failures between the solder balls and other components, such as de-lamination of low dielectric constant dielectric under the solder joints. Other failures include bridging failures, wherein the solder from one connection bridges over to an adjacent connection.